At present, a conventional machine for coating pharmaceutical products comprises a hollow pan that revolves about a horizontal axis and is known in the trade by the term “Pellegrini coating pan”, which will herein be referred to simply as “coating pan”.
At the front of it, the coating pan has a central, circular opening through which the pharmaceutical products are fed into the pan from a reservoir, and a plurality of nozzles, mounted on an arm extending in a direction substantially parallel to the axis of rotation of the pan and designed to spray a coating liquid towards and over a mass of pharmaceutical products to be treated, lying centrally inside the pan and coming from the reservoir through the central opening.
At present, the inside walls of the coating pan are preferably equipped with a plurality of inclined baffles protruding radially from the walls themselves. These baffles facilitate uniform distribution of the mass of products not only while the coating pan rotates clockwise about its axis as the products to be treated are fed into it but also while the coating pan rotates in the opposite direction as the treated product is fed out of the coating pan into a container placed at the central opening beforehand.
A major drawback in a coating machine of this kind is that the pan has a single opening for infeed of the untreated product still to be treated, as well as for outfeed of the treated product. This creates a potential risk of contamination between incoming and outgoing products, especially when there is a change to a different type of coating material.
The present invention has for an object to provide a machine for treating pharmaceutical products that overcomes the above mentioned drawback.
Another object of the present invention is to provide a coating machine that makes the treatment of the pharmaceutical products as safe and rational as possible and that also permits rapid cleaning and sterilising of the coating pan.